Remove the cover off the engine and take a look at the charge pipe on the Driver's side. You should see the MAF sensor and the 3/8" vacuum line just prior to it. If you follow this line you will see that it goes to a Tee. One side goes to the intake manifold (I believe) and the other goes to the intake just prior to the turbo. There is NO check valve which means that this a direct boost leak. This is the reason for laggy boost and boost dropping off on the top end. I removed the hose on the charge pipe (driver's side). I place a rubber/plastic cap on the tube then placed the hose back on it. This effectively blocked off the flow. Now I have more TQ down low with a quicker spool and more HP up top with no boost leaks. The car is enjoyably to drive.